Friction draft gear



Jan. 2, v1934. A, F. STUEB|NG 1,942,377

FRICTION DRAFT GEAR Jan. 2, 1934. A. F. sTuEBlNG FRICTION DRAFT GEARFiled June 17. 1930 3 Sheets-Sheet 2 24 ll 16mm' Jan. 2, 1934. A. F.sTUEBlNG 1,942,377

FRICTION DRAFT GEAR Filed June 17, 1930 3 Sheets-Sheet 3 JJ.A55/1555.12.

JJ J6 2O l Patented Jan. 2, 1934 UNITED STATES TNTS OFFICE v14 claims.

My invention relates to friction draft gears for railway cars and it hasfor one of its objects the provision of improved means for facilitatingthe release of the friction elements of the gear.

Another object of the invention is to provide an improved form ofhousing for the gear especially adapted to withstand the burstingstresses to which it is subjected.

A primary feature of the invention is to provide the draft gear with aplurality of friction elements, the frictional resistance of one of saidelements being greater than the friction resistance of the other.

Another feature of the invention is to provide l the gear with aload-sustaining member having a plurality of friction surfaces of unlikecontour.

A further feature of the invention consists in providing the draft gearwith a pair of friction elements disposed on opposite sides of thelongitudinal axis of the gear, said elements having opposed frictionsurfaces and one friction surface of one of the elements being ofdifferent contour than the corresponding friction surface of the otherof the elements.

A still further feature of the invention consists in forming the wallsof the gear housing which oppose the lateral forces exerted by thefriction elements, with a plurality of laterally projecting portionsextending transversely of the longitu- 30 dinal axis of the gear.

A still further feature of the invention consists in integrally formingthe walls of the draft gear housing with plate like portions spacedlaterally therefrom.

Other and more specic features of the invention residing in advantageousforms, combinations and relations of parts will hereinafter appear andbe pointed out in the claims.

' In the drawings illustrating a preferred ernbodiment of the invention:

Figure 1 is a view, partly in section and partly in plan of the draftgear.

Figure 2 is a view, partly in elevation and parti ly in section, of thegear taken at right angles to the View illustrated in Figure 1.

Figure 3 is an end View of the gear taken on line 3-3 of Figure 1.

Figures 4, 5 and 6 are views taken on lines 4-4, 5 5 and 6-6 of Figure1, respectively.

igure 7 is a side elevational View of the central wedge member.

Figure 8 is an end elevational view of the wedge member.

Figure 9 is a side elevational View of the wedge member as seen from theright hand side of Figure 7.

Figure 10 is an inside side elevational view of one of the frictionelements.

Figure 11 is a sectional view taken on line 60 11-11 of Figure 10.

Figure 12 is an end view of the friction element of Figure 10 as viewedfrom the righthand side of that ligure. y

Figure 13 is an inside side elevational View of 65 another one of thefrictional elements.v y

Figure 141s a sectional view taken on line 14-14 of Figure 13. n

Figure l5 is an end elevational View of the friction element of Figure13 as viewed from the 70 right hand side of that figure.

Referring more particularly to the drawings y1 indicates the draft gearhousing Which is adapted to be mounted in a yoke, diagrammaticallyillustrated at 2. The housing is preferably closed at its inner end by awall 3 and is formed with top and bottom walls 4 and 5, respectively,and with side walls 6 and 7, respectively. To prevent the housing frommoving inwardly, with respect to the car, its inner end mayadvstntageously be formed with laterally extending projections 8 adaptedto cooperate with suitable stops (not shown) Disposed within the forwardportion 9 of the housing are the relatively movable friction elementscomprising a central wedge 10 and a pair of shoes 11 and 12,respectively.V The central member 10 is formed with opposed frictionsur'- faces 13 and 14 respectively disposed in substantially verticalplanes forming equal angles with the longitudinal axis of the gear.

The shoe 11 is formed with opposed inner and outer frictional surfaces15 and 16, respectively. The inner surface 15 is adapted to be disposedin a plane substantially parallel with the adjacent frictional surface13 of the wedge member for cooperating therewith, The outer frictionalsurface 16 of the shoe is a plane surface and is adapted to be disposedin a substantially vertical plane for cooperatingV with acorrespondingly disposed frictional surface 17 formed on the interior ofthe adjacent wall 6 of the hous' ing. The friction surfaces 15 and 16which are disposed in planes forming an acute angle with each other areformed on plate-like portions 18 105 and 19. At their outer ends thesevplate-like portions intersect and continue as an outwardly extending lipor lug 20 normally disposed in spaced overlapping relation to theadjacent side of the wedge member l0. The plate-like porposed inner andouter frictional surfaces 26 and 27. The inner friction surface 26 isdisposed in a plane substantially parallel with the frictional surface14 of the central wedge member for cooperating therewith. The outerfrictional surface 27, however, instead of being a plane surface as isthe outer frictional surface 16 of the shoe 1l may be and preferably isformed as a curved substantially cylindrical surface and is adapted tocooperate with a similarly formed friction surface 28 on the interior ofthe portion 9 of the housing. Since the shoe 12 is .of the sameconstruction as the shoe l1, with the exception of the contour of itsouter frictional surface, corresponding parts of the two shoes aredesignated by similar reference numerals. It should, of course, be notedthat the plate portion 19 of the shoe 12, upon which the frictionsurface 27 is formed, is curved and the outwardly projecting lip or lug20 is, therefore, correspondingly curved as is the portion of the wedgemember which it overlaps.

To return the friction elements to the positions illustrated in Figures1 and 2, after they have been actuated by either bumng or draft forces,a plurality of springs 29 and 30 may be employed. The spring 29 mayconveniently engage the rear or inner wall 3 of the housing and theinwardly projecting portions 24 of both of the friction shoes while thespring 30 may bear against a boss 31 projectingr inwardly from the rea-rwall 3 and the portions 23 of both shoes. The friction elements mayadvantageously be retained in assembled position by a longitudinallyextending bolt 32. The head of the bolt is preferably disposed withinthe boss 31 and engages an annular portion 33 formed integrally with thelatter. The removable nut 34 of the bolt is preferably disposed within asuitably formed recess 35 in the central wedge member. In this manner itwill be perceived that the draft gear may be quickly and easilyassembled and shipped as a unit.

In the operation of the gear the central wedge member is actuated by afollower diagrammatically illustrated at 36. As is illustrated if thegear is operated by buing forces the follower 36 is moved inwardly by acoupler (not shown), the housing being held stationary in the mannerheretofore described, while if the gear is operated by draft forces thehousing moves toward the follower, the latter being held stationary bysuitable stops (not shown). In either event the force supplied to thewedge is transmitted to the friction shoes through the cooperatingwedging surfaces setting up lateral forces which press the shoes againstthe friction surfaces of the housing and also setting up forces tendingto move the shoes inwardly relatively to the latter. The inward movementof the shoes is resisted by the springs 29 and 30 and by the frictionforces between the shoes and the housing. The cooperating frictionsurfaces of the shoes and housing converge or taper inwardly so that thedistance between the shoes decreases as they are moved inwardly therebycausing relative movment between the wedge member and shoes, and furtherincreasing the frictional force between the various elements of thegear. Although the wedge exerts equal forces on the shoes 11 and 12, theforces acting between the housing and the shoe 11, provided with theplane friction surface 16, directly oppose and act in planes parallel tothe lateral components of the forces exerted by the Wedge on shoe 11while the forces acting between the housing and the shoe 12, providedwith the cylindrical friction surface 27, act toward the axis of thecurved surface. The resultant of all of the forces acting between thehousing and the shoe 12, with the exception of the ones acting throughthe horizontal center line of the cylindrical surface thereof, are,therefore, disposed at an angle to the lateral components of the forcestransmitted from the wedge to the shoe and consequently are of greatermagnitude than the last named forces. Thus, it will be appreciated thatsince the total pressure between the wedge and shoe 11 is equal to thetotal pressure between the housing and shoe 1l and the pressure betweenthe wedge and shoe l2 is the same as that between the wedge and shoe 11but is less than the pressure between the housing and shoe 12, the totalpressure and therefore the frictional resistance between the cylindricalsurfaces of the shoe 12 and the housing will be greater than the totalpressure and frictional resistance between plane surfaces of the shoe 11and the housing thereby causing a differential frictional resistance.With the parts of the gear in normal position the springs 29 and 30 willdeliver an equal pressure to the friction shoes. During the closure ofthe gear and due to the difference in frictional resistance between theflat face shoe and the housing and the cylindrical shoe and the housing,the flat face shoe will tend to move at a greater rate of speed than thecylindrical shoe. This tendency of the ilat face shoe to move at agreater rate of speed and therefore a greater distance than thecylindrical shoe will be to some extent counteracted by the springssince the latter will exert a greater resistance to the shoe moving thegreater distance. In the particular embodiment illustrated, thisdifference in frictional resistance between the shoes is, however, of noimportance during closure of the gear but is only advantageous tofacilitate release of the gear to enable the friction elements toquickly return to their normal positions. From the foregoing analysis ofthe force reactions between the shoes 11 and 12 and the housing it willbe perceived that the shoe 12 offers greater resistance to outwardmovement relatively to the housing than the shoe 11. Consequently thesprings 29 and 30 exert a greater force on the shoe 11 than on the shoe12 thereby moving the former outwardly and releasing the pressurebetween the wedge and shoe 12. Thus the release of the gear is greatlyfacilitated.

Due to the cylindrically cooperating faces of the shoe 12 and thehousing they shoe is adapted to rotate about the axis of its cylindricalsurface so as to compensate for deviation from parallelism of any of theplane surfaces of the gear. This, of course, results in an equaldistribution of the forces on all of the friction elements and thehousing.

In draft gear housings having opposed fric-l tion surfaces the Wallsconnecting the portions of the housing on which the friction surfacesare formed are in tension and it is in these walls that forces are setup opposing the lateral forces exerted by the gear elements. Since theopposing forces, however, donot act in the same planes as the lateralforces it will, of course, be appreciated that the sides of the housingon which the friction surfaces are formed are subjected to bendingmoments. In the form of housing illustrated in the drawings it will beperceived that the top and bottom walls e and 5, respectively, are intension while the side walls 6 and 7 are the ones subjected to bendingmoments. In order to prevent bending of the side walls 6 and 7 theportion 9 of these walls is formed with a greater amount of metal thanare the top and bottom walls 4 and 5 of this portion of the housing.Although this extra metal may be arranged a variety of ways it ispreferred to dispose it in the manner illustrated in the drawings. Thusthe walls 6 and 7 are each formed with a plurality of laterallyprojecting portions 37 extending transversely of the longitudinal axisof the gear.

t their outer ends these portions are integrally connected by plate-likeportions 38 spaced laterally of the adjoining walls of the housing andpreferably disposed in substantially vertical planes. The hollow boxshape reinforcements thus formed greatly increase the strength of theside walls without materially increasing the weight of the casting andby maintaining a substantial uniformity of cross section the danger ofshrinkage cracks and like defects in the casting operation is avoided.

I claim:

1. A draft gear for railway cars involving a load sustaining columnmember, movable elements respectively having friction surfaces inengagement with the column member, wedging means for actuating saidelements, and spring means opposing movement of said elements, saidelements having wedging faces inclined in Vhe same direction withrespect to the longitudinal axis of the gear for cooperating with saidmeans, the contours of the friction surfaces of said elements and theinclination of said wedging faces being such that the summation of thefriction producing forces between the column member and one of saidfriction surfaces is greater than the summation of the frictionproducing forces between the column member and another of said surfaces.

2. A gear for railway cars involving a load sustaining column member,movable elements respectively having friction surfaces in engagementwith the column member, wedging means for actuating said elements, andspring means for opposing movement of said elements, said elementshaving wedging faces inclined in the same direction with respect to thelongitudinal axis of the gear for cooperating with said wedging means,the engaging friction surfaces of one of said elements and the housingbeing curved and having greater surface Contact transversely of thelongitudinal axis of the gear than the engaging friction surfaces ofanother of said elements and the housinfJr so as to produce a greaterfriction force between the rst mentioned sets of engaging frictionsurfaces than between the second mentioned sets of engaging frictionsurfaces.

3. A draft gear for railway cars involving a housing provided with twofriction surfaces, elements movable relatively to said housing andrespectively having wedging faces inclined in the same direction withrespect to the longitudinal axis of the gear, spring means opposingmovement of said elements, and wedging means for actuating said frictionelements having faces respectively engagement with the wedging faces ofthe latter, said elements 'espectively having friction surfaces inengagement with the surfaces of the housing, the engaging frictionsurfaces of one of the elements and housing being of such d rent contourfrom the engaging friction surfaces of the other element and housing asto produce a greater friction force between one of the sets of saidengaging friction surfaces than between the other of the sets offriction surfaces, and the inclination of Y said wedging laces beingsuch as to maintain the difference in friction forces between said setsof friction surfaces.

4. A draft gear for railway cars involving a load sustaining columnmember, elements movable relatively to the column member andrespectively having friction surfaces in engagement with the latter,spring means opposing movement of said elements, and wedginer meanshaving faces inclined in the same direction with respect to thelongitudinal axis of the gear for cooperating with said elements, thefriction surface of one of said elements having a curved portion and thefriction surface of another of said elements having a plane portion,said friction surfaces being so arranged and the inclination of thewedging faces being such that the summation of the friction producingforces between one of said elements and the column member is greaterthan the summation of the friction producing forces between another ofsaid elements and the column member.

5. A draft gear for railway cars involving a load sustaining columnmember having two friction surfaces, one of said surfaces being planeand the other of said surfaces being curved, wedging means, movablefriction elements, and spring means opposing movement of said elements,said elements being movable relatively to the column member andrespectively provided with faces inclined in the same direction withrespect to the longitudinal axis of the gear for cooperating with saidwedging means, said elementsalso respectively having surfaces inengagement with said plane and curved friction surfaces of the columnmember, said friction surfaces being so arranged and the inclination ofthe wedging faces being such that the summation of the frictionproducing forces between the said column member and the element inengagement with said curved surface is greater than the summation of thefriction producing forces between the column member and the element inengagement with said plane surface.

6. A draft gear for railway cars involving a housing, friction elementsdisposed within the housing and movable relatively thereto, a wedgingmember interposed between the friction elements, and spring meansopposing movement of said elements, said elements respectively havingfaces inclined in the same direction with respect to the longitudinalaxis of the gear for cooperating with said wedging member, one of saidfriction elements having a curved surface in engagement with the housingand the other of said elements having a substantially plane surface inengagement with the housing, said friction surfaces being so arrangedand the inclination of the wedging faces being such that the summationof the friction producing forces between the Vfirst named element andhousing is greater than the summation of the friction producing forcesbetween the last named element and housing.

'7. A draft gear for railway cars involving a housing, a movable centralWedge member disposed within the housing and having wedging facesrespectively forming equal angles with the axis of movement of thewedge, movable friction elements operatively interposed between thewedge and housing and having surfaces in frictional engagement with thelatter, and spring means opposing movement of said elements, saidelements also respectively having faces inclined in the same directionwith respect to the axis of movement of the wedge for cooperating withthe faces of said wedge, the friction surface of one of said elementsbeing of such different contour from the friction surface of another ofsaid elements that the summation of the friction producing forcesbetween one of the elements and the housing is greater than thesummation of the friction producing forces between another of theelements and the housing.

8. A draft gear for railway cars involving a housing having frictionsurfaces, a central wedge member movable within said housing, twomovable friction elements arranged on opposite sides of the wedgemember, and spring means opposing movement of said elements, saidelements respectively having wedging surfaces and friction surfaces,said friction surfaces being in engagement with the friction surfaces ofthe housing and said wedging surfaces being inclined in the samedirection with respect to the longitudinal axis of the gear and being inengagement with said wedging member, the engaging friction surfaces ofone of said elements and housing being of such different contour fromthe engaging friction surfaces of the other of said elements and housingas to produce a greater friction force between one of the sets ofengaging friction surfaces than between the other of the said sets offriction surfaces, and the inclination of the wedgng surfaces being suchas to maintain the diiference in friction force between said sets offriction surfaces.

9. A draft gear for railway cars involving a housing, a central wedgemember movable within said housing, a pair of movable friction elementsrespectively having faces inclined in the same direction with respect tothe longitudinal axis of the gear in engagement with said wedge member,and spring means opposing movement of said elements, one of the elements0f said pair being disposed on one side of the wedge member and theother element thereof being disposed on the opposite side, each of saidelements having a friction surface in engagement with the housing, thefriction surface of one of the elements being a substantially planesurface and the friction surface of the other of the elements being acurved surface, said friction surfaces being so arranged and theinclination of the wedging faces being such that the summation of thefriction producing forces between the last-named element and the housingis greater than the summation of the friction producing forces betweenthe secondnamed element and the housing.

10. A draft gear for railway cars involving a load sustaining columnmember having friction surfaces, wedging means having inwardlyconverging surfaces, movable friction elements respectively interposedbetween the column member and the wedging means, and spring meansopposing movement of said elements, each of said elements havingsurfaces respectively in engagement with the surfaces of said columnmember and said wedging means, said wedging means being adapted to exertequal pressures on said elements and the cooperating surfaces of one ofsaid elements and the column member being such different contour fromthe cooperating surfaces of another of said elements and the columnmember that the summation of the friction producing forces between oneof said elements and the column member is greater than the summation ofthe friction producing forces between another of said elements and thecolumn member.

11. A draft gear for railway cars involving a housing having frictionsurfaces, wedging means having opposed inwardly converging wedging facesforming equal angles with the longitudinal axis of the gear, a pluralityof movable friction elements operatively interposed between the housingand wedging means, and means for opposing movement of said elements,each of said elements having a friction surface in engagement with oneof said surfaces of the housing and a wedging surface in engagement withthe wedging means, the engaging friction surfaces of one of saidelements and housing being so formed with respect to the engagingfriction surfaces of another of said elements and housing as to producea greater friction force between one of the sets of said engagingfriction surfaces than between another of said sets of frictionsurfaces.

l2. A draft gear for railway cars involving a housing having frictionsurfaces, wedging means having surfaces inclined in the same directionwith respect to the longitudinal axis of the gear, friction elementsrespectively interposed between the housing and the wedging means, andspring means opposing movement of said elements, each of said elementshaving surfaces respectively in engagement with the surfaces of saidhousing and said wedging means, said wedging means being adapted toexert equal pressures on said elements and the cooperating surfaces ofone of said elements and the housing being of such different contourfrom the cooperating surfaces of another of said elements and thehousing that one of said elements exerts greater pressure on said columnmember than the other of said elements.

13. A draft gear for railway cars involving a load sustaining colurnnmember, movable elements respectively having friction surfaces inengagement with the column member, wedging means having surfacesinclined in the same direction with respect to the longitudinal axis ofthe gear respectively cooperable with said elements for actuating thelatter, and spring means opposing movement of said elements, thefriction surfaces of said elements being so formed that the ratio of thelateral component of the wedging force acting on one of said elements tothe frictional force acting between that element and the column memberis greater than the ratio of the lateral component of the wedging forceacting on another of said elements to the frictional force actingbetween the latter element and the column member.

lll. A draft gear for railway cars involving a load sustaining columnmember having friction surfaces, movable elements having frictionsurfaces respectively cooperable with said surfaces of the columnmember, said elements having wedging faces inclined in the samedirection with respect to the longitudinal axis of the gear, wedgingmeans having faces respectively cooperable with the wedging faces of theelements for actuating said elements, and spring means opposing Miltween another of said sets, and the inclination of the wedging faces ofthe elements and the Wedging means being such that the elementscooperate With the latter to maintain the difference in friction forcesbetween said sets of cooperating friction surfaces.

ALBERT F. STUEBING.

